Wireless subscriber growth helped the top U.S. phone company AT&T achieve quarterly profits. Wireless subscriber growth also helped to compensate for its shrinking traditional landline business.

Q2 profit rose to $3.8 billion from $2.9 billion from a year earlier. Quarterly revenue rose 4.7% to $30.9 billion.

Probably most notable was AT&T’s wireless division saw its churn fall to 1.1%, the lowest level in the company’s history. CEO Randall Stephenson pointed to the operator’s relationship with Apple as a way of showing how AT&T had transformed itself.

The company said sales of the iPhone 3G were twice that of results from the first launch in the first 12 days. AT&T added 1.3 million wireless subscribers in Q2, down 123,000 from a year ago. Wireless operating income was $3.1 billion in Q2, up 91% from a year ago, and operating margins were 25.5%, up from 15.4% a year ago.

AT&T said its primary consumer access lines fell 8.7% in the quarter from a year earlier.